Inflector irregular singularize rules
Fix ActionDispatch::Request#formats when HTTP_ACCEPT header is empty string
Remove i18n symbol dependency

date.order is the only key in rails i18n that is required to be a
symbol. This patch allows for symbols or strings which means:

* No requirement for symbol type in .yml files. A future
  YAML.safe_load wouldn't need to load symbols
* Rails could actually use json rather than yml as the backend
Don't change the original i18n data
Remove "Application" section title from routes

This PR standardizes the output of the HTML and console based routes to not include the title for "Application Routes" those that are defined by the application. Instead only routes defined in engines get any special treatment. 

Based on this conversation:

https://github.com/rails/rails/commit/af5c0fd85fce1adb311083dd1ecf96432ee8caa3#commitcomment-2458823

ATP actionpack /cc @carlosantoniodasilva 
Merge pull request #8995 from schneems/schneems/formatting-the-formatters

Remove "Application" section title from routes
Fix syntax error :grin:
Merge pull request #8977 from Soylent/master

Resovled issue rails#7774
Improve relation docs about to_sql and where_values_hash

* User class instead of Users.
* #where_values_hash does not change the value to downcase as the
  example was showing.

[ci skip]
Added ability to raise or log on unpermitted params.
Merge pull request #8999 from thomasfedb/raise_or_log_unpermitted_params

Raise or log unpermitted params.
Restore and adapt the implementation reverted at
https://github.com/rails/rails/commit/cc1c3c5be061e7572018f734e5239750ab449e3f

Now instead of raise, we log by default in development and test
Refactor ActiveSupport::Cache::Store#fetch.
Updated version of jQuery rails in gemfile
Merge pull request #9000 from sherwu/master

Updated Gemfile to use jQuery-rails v 2.2.0
Merge pull request #8081 from JoeyButler/refactor_cache_store

Refactor cache store
Merge pull request #8978 from chrismcg/remove_i18n_symbol_dependency

Remove i18n symbol dependency
Fix failing test about date.order translation values

Introduced in b718998f3e8e6f3d01ad138e40f08fbcc3736285.
Remove warning: shadowing outer local variable
Added test case to prevent regression of chained, preloaded scopes. (#7490)